Thursday 8 January 2009 14.10 EST
First published on Thursday 8 January 2009 14.10 EST

Rio Ferdinand has given Manchester United a boost ahead of Sunday's game against Chelsea at Old Trafford by informing Sir Alex Ferguson he feels ready to return after missing almost a month of Premier League action.

Ferdinand has not played since the goalless draw at Tottenham Hotspur on December 13, but came through a full training session today with no apparent reaction to his back problems.

The nature of his injury means that it is too early to be certain that he will be available but his progress has encouraged Ferguson to believe he should have his full-strength defence available again.

Patrice Evra is returning from his five-match domestic suspension and is expected to come straight back into the team at the expense of John O'Shea, while Ferdinand should take over from Jonny Evans in a defence that attracted strong criticism from Ferguson after Wednesday's 1–0 defeat to Derby County in the first leg of the Carling Cup semi-final.

United have brought in a 20-year-old Belgian defender, Ritchie De Laet, from Stoke on a three-year deal after the clubs agreed a performance-related payment package. De Laet joined Stoke from Royal Antwerp, United's feeder club, in August 2007 but has not played a single first-team game, and spent the early part of this season on loan at Wrexham.

Meanwhile, the young Chelsea striker Franco di Santo is at loggerheads with Luiz Felipe Scolari over his desire to represent his country in the South American Under-20 Championship, which starts on 19 January.

Di Santo has been called into Argentina's squad for the competition but says Chelsea's manager is unwilling to let him go because of a shortage of strikers at Stamford Bridge, where he has been understudying Nicolas Anelka and Didier Drogba. The Argentine football federation has referred the matter to Fifa, which could rule that Chelsea must allow Di Santo to go.

"I spoke to Scolari and he told me that he wouldn't let me go," Di Santo told Argentine television . "There are only three strikers in the squad: Didier Drogba, Nicolas Anelka and me, and he told me that he needs me to stay in London."

The 19-year-old added that Chelsea's captain, John Terry, had backed him in wanting to go to Venezuela for the tournament, which runs to 8 February: "I spoke to John Terry a couple of times in the last couple of days and he said I was right to want to go and play. He said I'm only on the bench and need to get minutes in the team so I get noticed. I'm always on the bench. I've only played eight games this season, always coming on in the last 10 or 15 minutes."

Reports in Argentina suggest the national coach, Diego Maradona, will speak to Chelsea in an attempt to convince them to release Di Santo. "It makes me proud that Maradona is interested in my case," Di Santo said.

The Almeria player Pablo Piatti is in an identical situation to Di Santo. Argentina's Under-20 coach, Sergio Batista, said: "We are still waiting to see if Pablo Piatti and Franco di Santo can play for us. We have to wait and see what Fifa say. We are anxious for them to join us but we have to wait."